Network Working Group M. Jenkins
Internet Draft National Security Agency
Intended Status: Informational M. Peck
Expires: April 4, 2014 The MITRE Corporation
K. Burgin
October 1, 2013
AES Encryption with HMAC-SHA2 for Kerberos 5
draft-ietf-kitten-aes-cbc-hmac-sha2-00
Abstract
This document specifies two encryption types and two corresponding
checksum types for Kerberos 5. The new types use AES in CBC mode
with plaintext padding for confidentiality and HMAC with a SHA-2 hash
for integrity.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Protocol Key Representation . . . . . . . . . . . . . . . . . 3
3. Key Generation from Pass Phrases . . . . . . . . . . . . . . . 3
4. Key Derivation Function . . . . . . . . . . . . . . . . . . . 4
5. Kerberos Algorithm Protocol Parameters . . . . . . . . . . . . 5
6. Checksum Parameters . . . . . . . . . . . . . . . . . . . . . 7
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
8. Security Considerations . . . . . . . . . . . . . . . . . . . 7
8.1. Random Values in Salt Strings . . . . . . . . . . . . . . 8
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 8
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
10.1. Normative References . . . . . . . . . . . . . . . . . . 8
10.2. Informative References . . . . . . . . . . . . . . . . . 8
Appendix A. Test Vectors . . . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15
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1. Introduction
This document defines two encryption types and two corresponding
checksum types for Kerberos 5 using AES with 128-bit or 256-bit keys.
The plaintext is padded to a multiple of the AES block size using the
algorithm in Section 6.3 of [RFC5652]. The new types conform to the
framework specified in [RFC3961], but do not use the simplified
profile.
The encryption and checksum types defined in this document are
intended to support NSA's Suite B Profile for Kerberos [suiteb-
kerberos] which requires the use of SHA-256 or SHA-384 as the hash
algorithm. Differences between the encryption and checksum types
defined in this document and existing Kerberos encryption and
checksum types are:
* The pseudorandom function used by PBKDF2 is HMAC-SHA-256 or HMAC-
SHA-384.
* A key derivation function from [SP800-108] which uses the SHA-256
or SHA-384 hash algorithm is used to produce keys for encryption,
integrity protection, and checksum operations.
* The plaintext is padded so the resulting length is a multiple of
the AES block length. This allows for AES encryption using CBC
mode as defined in [SP800-38A] instead of using ciphertext
stealing (CTS) mode.
* The random nonce used during content encryption is sent as part of
the ciphertext, instead of using a confounder. This saves one
encryption and decryption operation per message.
* The HMAC is calculated over the random nonce concatenated with the
AES output, instead of being calculated over the confounder and
plaintext. This allows the message receiver to verify the
integrity of the message before decrypting the message.
* The HMAC algorithm uses the SHA-256 or SHA-384 hash algorithm for
integrity protection and checksum operations.
2. Protocol Key Representation
The AES key space is dense, so we can use random or pseudorandom
octet strings directly as keys. The byte representation for the key
is described in [FIPS197], where the first bit of the bit string is
the high bit of the first byte of the byte string (octet string).
3. Key Generation from Pass Phrases
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The pseudorandom function used by PBKDF2 will be the SHA-256 or SHA-
384 HMAC of the passphrase and salt. If the enctype is "aes128-cbc-
hmac-sha256-128", then HMAC-SHA-256 is used as the PRF. If the
enctype is "aes256-cbc-hmac-sha384-192", then HMAC-SHA-384 is used as
the PRF.
The final key derivation step uses the algorithm KDF-HMAC-SHA2
defined below in Section 4.
If no string-to-key parameters are specified, the default number of
iterations is 32,768.
To ensure that different long-term keys are used with different
enctypes, we prepend the enctype name to the salt string, separated
by a null byte. The enctype name is "aes128-cbc-hmac-sha256-128" or
"aes256-cbc-hmac-sha384-192" (without the quotes). The user's long-
term key is derived as follows
saltp = enctype-name | 0x00 | salt
tkey = random-to-key(PBKDF2(passphrase, saltp,
iter_count, keylength))
key = KDF-HMAC-SHA2(tkey, "kerberos") where "kerberos" is the
byte string {0x6b65726265726f73}.
where the pseudorandom function used by PBKDF2 is HMAC-SHA-256 when
the enctype is "aes128-cbc-hmac-sha256-128" and HMAC-SHA-384 when the
enctype is "aes256-cbc-hmac-sha384-192", the value for keylength is
the AES key length, and the algorithm KDF-HMAC-SHA2 is defined in
Section 4.
4. Key Derivation Function
We use a key derivation function from Section 5.1 of [SP800-108]
which uses the HMAC algorithm as the PRF. The counter i is expressed
as four octets in big-endian order. The length of the output key in
bits (denoted as k) is also represented as four octets in big-endian
order. The "Label" input to the KDF is the usage constant supplied
to the key derivation function, and the "Context" input is null.
Each application of the KDF only requires a single iteration of the
PRF, so n = 1 in the notation of [SP800-108].
In the following summary, | indicates concatenation. The random-to-
key function is the identity function, as defined in Section 3. The
k-truncate function is defined in [RFC3961], Section 5.1.
When the encryption type is aes128-cbc-hmac-sha256-128, the output
key length k is 128 bits for all applications of KDF-HMAC-SHA2(key,
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constant) which is computed as follows:
K1 = HMAC-SHA-256(key, 00 00 00 01 | constant | 0x00 | 00 00 00 80)
KDF-HMAC-SHA2(key, constant) = random-to-key(k-truncate(K1))
When the encryption type is aes256-cbc-hmac-sha384-192, the output
key length k is 256 bits when computing the base-key and Ke, and the
output key length k is 192 bits when deriving Kc and Ki. KDF-HMAC-
SHA2(key, constant) is computed as follows:
If deriving Kc or Ki (the constant ends with 0x99 or 0x55):
k = 192
K1 = HMAC-SHA-384(key, 00 00 00 01 | constant | 0x00 | 00 00 00 C0)
KDF-HMAC-SHA2(key, constant) = random-to-key(k-truncate(K1))
Otherwise (if deriving Ke or deriving the base-key from a
passphrase as described in Section 3):
k = 256
K1 = HMAC-SHA-384(key, 00 00 00 01 | constant | 0x00 | 00 00 01 00)
KDF-HMAC-SHA2(key, constant) = random-to-key(k-truncate(K1))
The constants used for key derivation are the same as those used in
the simplified profile.
5. Kerberos Algorithm Protocol Parameters
Each encryption will use a 16-octet nonce generated at random by the
message originator. The initialization vector (IV) used by AES is
obtained by xoring the random nonce with the cipherState.
CBC mode [SP800-38A] requires the plaintext length be a multiple of
the AES block size, so the plaintext is padded using the algorithm in
Section 6.3 of [RFC5652].
The ciphertext is the concatenation of the random nonce, the output
of AES in CBC mode, and the HMAC of the nonce concatenated with the
AES output. The HMAC is computed using either SHA-256 or SHA-384.
The output of HMAC-SHA-256 is truncated to 128 bits and the output of
HMAC-SHA-384 is truncated to 192 bits. Sample test vectors are given
in Appendix A.
Decryption is performed by removing the HMAC, verifying the HMAC
against the remainder, and then decrypting the remainder if the HMAC
is correct.
The following parameters apply to the encryption types aes128-cbc-
hmac-sha256-128 and aes256-cbc-hmac-sha384-192.
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protocol key format: as defined in Section 2.
specific key structure: three protocol-format keys: { Kc, Ke, Ki }.
required checksum mechanism: as defined in Section 6.
key-generation seed length: key size (128 or 256 bits).
string-to-key function: as defined in Section 3.
default string-to-key parameters: 00 00 80 00.
random-to-key function: identity function.
key-derivation function: KDF-HMAC-SHA2 as defined in Section 4. The
key usage number is expressed as four octets in big-endian order.
Kc = KDF-HMAC-SHA2(base-key, usage | 0x99)
Ke = KDF-HMAC-SHA2(base-key, usage | 0xAA)
Ki = KDF-HMAC-SHA2(base-key, usage | 0x55)
cipherState: a 128-bit random nonce.
initial cipherState: all bits zero.
encryption function: as follows, where E() is AES encryption in CBC
mode, h is the size of truncated HMAC, and c is the AES block size.
N = random nonce of length c (128 bits)
IV = N XOR cipherState
pad = Shortest string of non-zero length to bring the plaintext
to a length that is a multiple of c. The value of each
added octet equals the number of octets that are added.
C = E(Ke, plaintext | pad, IV)
H = HMAC(Ki, N | C)
ciphertext = N | C | H[1..h]
cipherState = N
decryption function: as follows, where D() is AES encryption in CBC
mode, and h is the size of truncated HMAC.
(N, C, H) = ciphertext
if H != HMAC(Ki, N | C)[1..h]
stop, report error
IV = N XOR cipherState
P | pad = D(Ke, C, IV)
cipherState = N
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pseudo-random function:
Kp = KDF-HMAC-SHA2(protocol-key, "prf")
PRF = HMAC(Kp, octet-string)
6. Checksum Parameters
The following parameters apply to the checksum types hmac-sha256-128-
aes128 and hmac-sha384-192-aes256, which are the associated checksums
for aes128-cbc-hmac-sha256-128 and aes256-cbc-hmac-sha384-192,
respectively.
associated cryptosystem: AES-128-CBC or AES-256-CBC as appropriate.
get_mic: HMAC(Kc, message)[1..h].
verify_mic: get_mic and compare.
7. IANA Considerations
IANA is requested to assign:
Encryption type numbers for aes128-cbc-hmac-sha256-128 and
aes256-cbc-hmac-sha384-192 in the Kerberos Encryption Type Numbers
registry.
Etype encryption type Reference
----- --------------- ---------
TBD1 aes128-cbc-hmac-sha256-128 [this document]
TBD2 aes256-cbc-hmac-sha384-192 [this document]
Checksum type numbers for hmac-sha256-128-aes128 and hmac-sha384-192-
aes256 in the Kerberos Checksum Type Numbers registry.
Sumtype Checksum type Size Reference
------- ------------- ---- ---------
TBD3 hmac-sha256-128-aes128 16 [this document]
TBD4 hmac-sha384-192-aes256 24 [this document]
8. Security Considerations
This specification requires implementations to generate random
values. The use of inadequate pseudo-random number generators
(PRNGs) can result in little or no security. The generation of
quality random numbers is difficult. [RFC4086] offers random number
generation guidance.
This document specifies a mechanism for generating keys from pass
phrases or passwords. The salt and iteration count resist brute
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force and dictionary attacks, however, it is still important to
choose or generate strong passphrases.
8.1. Random Values in Salt Strings
NIST guidance in Section 5.1 of [SP800-132] requires the salt used as
input to the PBKDF to contain at least 128 bits of random. Some
known issues with including random values in Kerberos encryption type
salt strings are:
* Cross-realm TGTs are currently managed by entering the same
password at two KDCs to get the same keys. If each KDC uses a
random salt, they won't have the same keys.
* The string-to-key function as defined in [RFC3961] requires the
salt to be valid UTF-8 strings. Not every 128-bit random string
will be valid UTF-8.
* Current implementations of password history checking will not
work.
* ktutil's add_entry command assumes the default salt.
9. Acknowledgements
Kelley Burgin was employed at the National Security Agency during
much of the work on this document.
10. References
10.1. Normative References
[RFC3961] Raeburn, K., "Encryption and Checksum Specifications for
Kerberos 5", RFC 3961, February 2005.
[RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)",
RFC5652, September 2009.
[FIPS197] National Institute of Standards and Technology,
"Advanced Encryption Standard (AES)", FIPS PUB 197,
November 2001.
10.2. Informative References
[RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker,
"Randomness Requirements for Security", BCP 106, RFC
4086, June 2005.
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[SP800-38A] National Institute of Standards and Technology,
"Recommendation for Block Cipher Modes of Operation:
Methods and Techniques", NIST Special Publication
800-38A, December 2001.
[SP800-108] National Institute of Standards and Technology,
"Recommendation for Key Derivation Using Pseudorandom
Functions", NIST Special Publication 800-108, October
2009.
[SP800-132] National Institute of Standards and Technology,
"Recommendation for Password-Based Key Derivation, Part
1: Storage Applications", NIST Special Publication 800-
132, June 2010.
[suiteb-kerberos]
Burgin, K. and K. Igoe, "Suite B Profile for
Kerberos 5", internet-draft draft-burgin-kerberos-
suiteb-01, Work In Progress, 2012.
Appendix A. Test Vectors
Sample results for string-to-key conversion:
--------------------------------------------
Iteration count = 32768
Pass phrase = "password"
Saltp for creating 128-bit master key:
61 65 73 31 32 38 2D 63 62 63 2D 68 6D 61 63 2D
73 68 61 32 35 36 2D 31 32 38 00 10 DF 9D D7 83
E5 BC 8A CE A1 73 0E 74 35 5F 61 41 54 48 45 4E
41 2E 4D 49 54 2E 45 44 55 72 61 65 62 75 72 6E
(The saltp is "aes128-cbc-hmac-sha256-128" | 0x00 |
random 16 byte valid UTF-8 sequence | "ATHENA.MIT.EDUraeburn")
128-bit master key:
C3 19 22 E2 EA 3A 67 05 E0 B9 AC 57 08 82 48 28
Saltp for creating 256-bit master key:
61 65 73 32 35 36 2D 63 62 63 2D 68 6D 61 63 2D
73 68 61 33 38 34 2D 31 39 32 00 10 DF 9D D7 83
E5 BC 8A CE A1 73 0E 74 35 5F 61 41 54 48 45 4E
41 2E 4D 49 54 2E 45 44 55 72 61 65 62 75 72 6E
(The saltp is "aes256-cbc-hmac-sha384-192" | 0x00 |
random 16 byte valid UTF-8 sequence | "ATHENA.MIT.EDUraeburn")
256-bit master key:
77 73 83 E7 C4 76 1D CE FC 5B D8 F8 A7 28 37 8A
5E 63 BC B2 0E B9 A2 BB C5 1E 73 56 8A FC CD E6
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Sample results for key derivation:
----------------------------------
enctype aes128-cbc-hmac-sha256-128:
128-bit master key:
37 05 D9 60 80 C1 77 28 A0 E8 00 EA B6 E0 D2 3C
Kc value for key usage 2 (constant = 0x0000000299):
B3 1A 01 8A 48 F5 47 76 F4 03 E9 A3 96 32 5D C3
Ke value for key usage 2 (constant = 0x00000002AA):
9B 19 7D D1 E8 C5 60 9D 6E 67 C3 E3 7C 62 C7 2E
Ki value for key usage 2 (constant = 0x0000000255):
9F DA 0E 56 AB 2D 85 E1 56 9A 68 86 96 C2 6A 6C
enctype aes256-cbc-hmac-sha384-192:
256-bit master key:
6D 40 4D 37 FA F7 9F 9D F0 D3 35 68 D3 20 66 98
00 EB 48 36 47 2E A8 A0 26 D1 6B 71 82 46 0C 52
Kc value for key usage 2 (constant = 0x0000000299):
EF 57 18 BE 86 CC 84 96 3D 8B BB 50 31 E9 F5 C4
BA 41 F2 8F AF 69 E7 3D
Ke value for key usage 2 (constant = 0x00000002AA):
56 AB 22 BE E6 3D 82 D7 BC 52 27 F6 77 3F 8E A7
A5 EB 1C 82 51 60 C3 83 12 98 0C 44 2E 5C 7E 49
Ki value for key usage 2 (constant = 0x0000000255):
69 B1 65 14 E3 CD 8E 56 B8 20 10 D5 C7 30 12 B6
22 C4 D0 0F FC 23 ED 1F
Sample encryptions (using the default cipher state):
----------------------------------------------------
Plaintext: (empty)
Nonce:
7E 58 95 EA F2 67 24 35 BA D8 17 F5 45 A3 71 48
128-bit AES key:
9B 19 7D D1 E8 C5 60 9D 6E 67 C3 E3 7C 62 C7 2E
128-bit HMAC key:
9F DA 0E 56 AB 2D 85 E1 56 9A 68 86 96 C2 6A 6C
AES Output:
9E 30 E1 7A 01 BC E8 5B 59 90 C8 90 1A 55 1D 8C
HMAC Output:
0C 80 06 07 A4 6E 35 2C A7 73 CE 52 69 51 63 57
Ciphertext:
7E 58 95 EA F2 67 24 35 BA D8 17 F5 45 A3 71 48
9E 30 E1 7A 01 BC E8 5B 59 90 C8 90 1A 55 1D 8C
0C 80 06 07 A4 6E 35 2C A7 73 CE 52 69 51 63 57
Plaintext: (length less than block size)
00 01 02 03 04 05
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Nonce:
7B CA 28 5E 2F D4 13 0F B5 5B 1A 5C 83 BC 5B 24
128-bit AES key:
4E FD A6 52 4E 6B 56 B4 F2 12 61 FB FC 93 21 AB
128-bit HMAC key:
29 1B 0C 37 73 D7 6E E6 BA 2C CF 1E 03 93 F6 3E
AES Output:
2B E8 63 D7 B1 D4 F0 4D 95 F2 17 D6 9E C2 14 23
HMAC Output:
5F D1 CB B9 C0 6E 42 6E F9 95 05 B5 FB 42 6F 6A
Ciphertext:
7B CA 28 5E 2F D4 13 0F B5 5B 1A 5C 83 BC 5B 24
2B E8 63 D7 B1 D4 F0 4D 95 F2 17 D6 9E C2 14 23
5F D1 CB B9 C0 6E 42 6E F9 95 05 B5 FB 42 6F 6A
Plaintext: (length equals block size)
00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
Nonce:
56 AB 21 71 3F F6 2C 0A 14 57 20 0F 6F A9 94 8F
128-bit AES key:
FF 82 40 42 4B CC BA 05 56 50 C0 39 3B 83 DF 3B
128-bit HMAC key:
ED 15 62 8B 45 35 8C BF 7F 50 E7 64 C2 6B 8A 1A
AES Output:
AD 5D 0C E8 93 48 A8 16 07 11 09 75 6A 83 FB 09
D2 3F 29 30 68 F9 D4 E5 1F B8 92 B0 61 C7 43 BF
HMAC Output:
3A 40 51 A4 8B 7A 11 B3 91 F1 36 67 98 16 24 AD
Ciphertext:
56 AB 21 71 3F F6 2C 0A 14 57 20 0F 6F A9 94 8F
AD 5D 0C E8 93 48 A8 16 07 11 09 75 6A 83 FB 09
D2 3F 29 30 68 F9 D4 E5 1F B8 92 B0 61 C7 43 BF
3A 40 51 A4 8B 7A 11 B3 91 F1 36 67 98 16 24 AD
Plaintext: (length greater than block size)
00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
10 11 12 13 14
Nonce:
A7 A4 E2 9A 47 28 CE 10 66 4F B6 4E 49 AD 3F AC
128-bit AES key:
B5 9B 88 75 AD 5D CA FF F7 79 4D 93 F8 19 9D 79
128-bit HMAC key:
0A 42 1D 72 2F 8F C2 D6 84 8B 1C DA D1 5A 49 C9
AES Output:
DA A3 99 2E 39 5C 5D E1 34 EB 1A CC 73 8D CE 02
35 B9 D6 5A 63 0B 8D 84 BC 78 E9 38 75 79 5E DF
HMAC Output:
CF 68 74 07 12 22 6C 61 C1 E4 A6 78 A9 7C 86 60
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Ciphertext:
A7 A4 E2 9A 47 28 CE 10 66 4F B6 4E 49 AD 3F AC
DA A3 99 2E 39 5C 5D E1 34 EB 1A CC 73 8D CE 02
35 B9 D6 5A 63 0B 8D 84 BC 78 E9 38 75 79 5E DF
CF 68 74 07 12 22 6C 61 C1 E4 A6 78 A9 7C 86 60
Plaintext: (empty)
Nonce:
F7 64 E9 FA 15 C2 76 47 8B 2C 7D 0C 4E 5F 58 E4
256-bit AES key:
0F A2 0D 7D 03 33 EE 65 16 2C DA 67 E7 AD 0D 3C
5E 03 1F 3B 66 70 E0 31 28 2F AC C2 87 9C 21 C7
192-bit HMAC key:
53 BF 30 6A 68 33 A3 25 18 FC B8 5F 63 1D 03 D5
2E E3 1B 39 75 2F 57 ED
AES Output:
73 1E 56 A3 D9 DA 70 87 5C 74 C7 67 73 C2 F7 EB
HMAC Output:
FA F7 49 55 33 7E 20 98 C4 B4 F7 8F 35 5B 8A B9
72 6D 40 AC F3 5D B3 7B
Ciphertext:
F7 64 E9 FA 15 C2 76 47 8B 2C 7D 0C 4E 5F 58 E4
73 1E 56 A3 D9 DA 70 87 5C 74 C7 67 73 C2 F7 EB
FA F7 49 55 33 7E 20 98 C4 B4 F7 8F 35 5B 8A B9
72 6D 40 AC F3 5D B3 7B
Plaintext: (length less than block size)
00 01 02 03 04 05
Nonce:
B8 0D 32 51 C1 F6 47 14 94 25 6F FE 71 2D 0B 9A
256-bit AES key:
47 DA 4C A2 8B D1 C1 14 D5 50 7E 55 81 86 CA 4F
DB A0 DA E5 B2 4F 6D 68 89 D5 3A FB F1 D0 B8 36
192-bit HMAC key:
13 6B 5C 83 C9 53 AE 29 E2 C2 31 6A 7B 34 B8 C2
AD 26 E4 66 7F AB 42 6E
AES Output:
EF DE 87 A1 14 2D B5 C7 4A 42 52 A7 A7 77 5A 3E
HMAC Output:
45 02 19 E4 A8 C6 3E 8F E6 DB F5 08 78 E4 28 40
E9 36 DD 0A 66 1C A9 9C
Ciphertext:
B8 0D 32 51 C1 F6 47 14 94 25 6F FE 71 2D 0B 9A
EF DE 87 A1 14 2D B5 C7 4A 42 52 A7 A7 77 5A 3E
45 02 19 E4 A8 C6 3E 8F E6 DB F5 08 78 E4 28 40
E9 36 DD 0A 66 1C A9 9C
Plaintext: (length equals block size)
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00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
Nonce:
53 BF 8A 0D 10 52 65 D4 E2 76 42 86 24 CE 5E 63
256-bit AES key:
5E A6 16 D8 FD A2 33 F1 B4 99 79 A4 B9 FA 01 D3
21 B1 3D 6F BD 6E 3B B7 2E 54 B4 85 E2 36 AF 23
192-bit HMAC key:
AD D3 8D C9 86 83 C5 CC 14 E3 C7 37 EA A7 06 47
B3 19 71 0E 87 6A 38 77
AES Output:
E4 09 FF 7A 93 60 E9 72 7B 3F 88 35 28 73 E0 CF
B3 21 90 09 69 7D 79 6A 51 9C A3 86 DF 84 5D AD
HMAC Output:
60 75 75 AA D0 05 9F 9A C8 16 EA E0 B9 B5 00 2E
42 33 AA 53 89 9F AB 39
Ciphertext:
53 BF 8A 0D 10 52 65 D4 E2 76 42 86 24 CE 5E 63
E4 09 FF 7A 93 60 E9 72 7B 3F 88 35 28 73 E0 CF
B3 21 90 09 69 7D 79 6A 51 9C A3 86 DF 84 5D AD
60 75 75 AA D0 05 9F 9A C8 16 EA E0 B9 B5 00 2E
42 33 AA 53 89 9F AB 39
Plaintext: (length greater than block size)
00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
10 11 12 13 14
Nonce:
76 3E 65 36 7E 86 4F 02 F5 51 53 C7 E3 B5 8A F1
256-bit AES key:
B3 A8 02 E3 40 61 3E F1 E0 EC E9 1A 15 7C 59 12
6F BD C4 B8 C2 4C 8D 0B 2E 5A 30 F0 1E 7E 34 88
192-bit HMAC key:
FC 0B 49 9B 83 55 A3 2A C3 C9 AC B6 64 93 63 EB
5D BB A4 25 1A 75 B2 0A
AES Output:
F6 2D D7 FF 39 A8 EE D2 4C C5 A8 CF 84 15 71 1C
F5 05 05 2F 9B AD 75 C8 27 9D 05 D4 81 CF A9 73
HMAC Output:
DB 3B C2 37 0F 9D A6 F1 F7 99 32 A0 A6 4F 7A 7A
BD B9 B3 35 47 DD 9B 62
Ciphertext:
76 3E 65 36 7E 86 4F 02 F5 51 53 C7 E3 B5 8A F1
F6 2D D7 FF 39 A8 EE D2 4C C5 A8 CF 84 15 71 1C
F5 05 05 2F 9B AD 75 C8 27 9D 05 D4 81 CF A9 73
DB 3B C2 37 0F 9D A6 F1 F7 99 32 A0 A6 4F 7A 7A
BD B9 B3 35 47 DD 9B 62
Sample checksums:
-----------------
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Internet-Draft AES-CBC HMAC-SHA2 For Kerberos 5 October 1, 2013
Checksum type: hmac-sha256-128-aes128
128-bit master key:
37 05 D9 60 80 C1 77 28 A0 E8 00 EA B6 E0 D2 3C
128-bit HMAC key (Kc, key usage 2):
B3 1A 01 8A 48 F5 47 76 F4 03 E9 A3 96 32 5D C3
Plaintext:
00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
10 11 12 13 14
Checksum:
D7 83 67 18 66 43 D6 7B 41 1C BA 91 39 FC 1D EE
Checksum type: hmac-sha384-192-aes256
256-bit master key:
6D 40 4D 37 FA F7 9F 9D F0 D3 35 68 D3 20 66 98
00 EB 48 36 47 2E A8 A0 26 D1 6B 71 82 46 0C 52
192-bit HMAC key (Kc, key usage 2):
EF 57 18 BE 86 CC 84 96 3D 8B BB 50 31 E9 F5 C4
BA 41 F2 8F AF 69 E7 3D
Plaintext:
00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
10 11 12 13 14
Checksum:
45 EE 79 15 67 EE FC A3 7F 4A C1 E0 22 2D E8 0D
43 C3 BF A0 66 99 67 2A
Jenkins, et al. Expires April 4, 2014 [Page 14]
Internet-Draft AES-CBC HMAC-SHA2 For Kerberos 5 October 1, 2013
Authors' Addresses
Michael J. Jenkins
National Security Agency
EMail: mjjenki@tycho.ncsc.mil
Michael A. Peck
The MITRE Corporation
EMail: mpeck@mitre.org
Kelley W. Burgin
Email: kelley.burgin@gmail.com
Jenkins, et al. Expires April 4, 2014 [Page 15]
